1. Field of the Invention
The invention relates to a multimode fuel injector for combustion chambers, particularly the combustion chamber of a jet engine. More particularly it concerns a refinement making it possible to ensure better peripheral atomisation.
2. Description of the Related Art
The fuel is introduced via several fuel injectors into a traditional combustion chamber of a gas turbine engine. The fuel is mixed with air in each fuel injector before being introduced, then burned in the combustion chamber.
A multimode fuel injector is known, wherein the injection of fuel is differentiated according to the operating speed of the engine. For example, European Patent 1 369 644 describes a fuel injector in which two modes of injection are combined thanks to two coaxial fuel atomisation systems, fed respectively by two fuel distribution circuits, a primary circuit, with relatively low permanent flowrate, which makes it possible to introduce the fuel into a combustion zone, optimised for low engine speeds and a secondary circuit, with intermittent flowrate introducing the fuel into a combustion zone optimised for high engine speeds. For this purpose the atomisation system includes an atomisation head comprising a central nozzle fed by said primary circuit and a peripheral distribution chamber fed by the secondary circuit.
In the first system described, the quality of peripheral atomisation governs the amount of polluting emissions at high engine speed. The invention proposes a multimode fuel injector making it possible to limit the polluting emissions at high engine speed, particularly on takeoff.